Tuyere



Sept. 8, 1942. F. J. ZIPPLER TUYERE Filed July 29 1941 INVENTOR Franc/LsJ: Z/p o/er g zmu Patented Sept. 8, 1942 UNE'EED STATES PATENT OFFICETUYERE Application July 29, 1941, Serial No; 464,443

Claims.

My invention relates to metal-reducing fur-' naces, such as cupolas andblast-furnaces, and consists in improvements in the structure of thetuyres that deliver the essential blast of air into such furnaces, andin refinements in method.

The object of the invention is to increase the metal-reducing efiiciencyof such furnaces.

Another object is to provide a tuyre that is more effective and moreenduring in service.

The invention is of particular, though not exclusive, utility in theoperation of blast-furnaces, and in such association it will bedescribed. In the accompanying drawing, Figure I is a fragmentary,vertical sectional view of the porticn of a blast furnace side wall thatextends between the bosh and the hearth of the furnace. Ordinarily, fromeight to sixteen tuyres are arranged in circumferential succession insuch wall of a blast furnace, and in Fig. I two of the.

tuyeres are shown in elevation;

Figure II is a fragmentary view, showing to larger scale the tuyere ofthe invention in conventional assembly with a cooler and a blowpipe. Thetuyere and the cooler appear in axial section, and the blowpipe in sideelevation;

Figure III is a view in end elevation of the tuyere, as seen from theright of Fig. II;

Figure IV is a view of the tuyre in horizontal section, the plane ofsection being indicated at IVIV in Fig. III; and

Figure V is a view comparable with Fig. III, illustrating a modifiedform of the tuyere of the invention.

It will be understood that in the operation of a blast furnace thecircumferential line of' tuyeres delivers jets of preheated air into theportion of the furnace chamber that is located below the bosh, the boshbeing the portion of the structure that chiefly sustains the weight ofthe columnar charge of iron ore, limestone, and coke. The air thusintroduced into the lower portion of the furnace chamber percolatesupwardly through the body of the charge, and in no way efiects thereduction of the ore in the charge, the molten metal thus produceddraining from the charge and collecting in a pool on the furnace hearthat the bottom of the furnace chamber. As the operation progresses thebody of the charge, progressively diminished by the metallurgicalreactions within the furnace, descends gravitationally, whilereplenishment of the charge is made at the top of the furnace.

In accordance with the invention, I form. at

the nose of each tuyre a nozzle portion that provides an extension ofthe axial bore of the tuyere body through which air is delivered intothe furnace. Additionally, I provide in the tuyere body an auxiliarypassageway for air. The auxiliary passageway extends upwardly from theaxial bore of the tuyere, and opens through the tuyre body in a planewhich is perpendicular to the axis of the tuyere at the base of theextending nozzle portion. Through such passageway an auxiliary streamof. air is projected upwardly into the bottom of the furnace charge thatis sustained above the tuyereline, with the consequence that I effectmore thorough penetration of the air blast into the charge, withincrease in the depth of the zone of metallurgical reaction within thefurnace. The auxiliary stream of air sweeps the'projecting nozzleportion of the tuyere in a direction from base to tip, and therebyprotects the body of the tuyere in the region where it is mostvulnerable to the conditions of heat and attrition within the furnace.

Referring to the drawing, I illustrate a tuyere Zin which and in theoperation of which the invention may be realized. The body of the tuyreis in this case of frusto-conic'al form, including at its larger end 2aan annular seat 3, upon which the tuyere is supported in engagement witha complementary seat 4 formed. in the bore of a tuyere' holder or cooler5, secured in the blast furnace wall 6. The bore lot the tuyere isprovided with the usual annular seat 8 that receives the outlet end ofan air-deliver- .ing blow-pipe 9. The tuyre may be formed, as iscustomary, of copper or bronze, and its walls may be hollow, providing achamber ID for a body of cooling water. Threaded openings ll provide forthe connection of water pipes. to the tuyre, so that a continuouscirculation of water may be maintained in the chamber Ill,

The bore 1 ofthe tuyere is of circular cross section, and its walltapers to a cylindrical nozzle portion l2 that extends on the axis ofthe bore l forwardly, beyond the vertically disposed wall 2b of thetuyere. An auxiliary passageway I3 extends upwardly from the taperedboreof the tuyere, and opens through the wall 222'. While the nozzle portionI2 is of smaller external diameter than the inner end of thetuyerev bodyfrom which it extends, the bore la of such nozzle portion provides themain air-delivering passage of the tuyre; Th outlet of such nozzleportion extends in a planeperpendicular to the axis of the tuyere, andit will be noted that the sponding increase in the danger that the tuyrewill fail under the deleterious conditions within the furnace. Theextending nozzle portion I2 provides accurate directional control of theblast of air delivered into the furnace, and the stream of air flowingfrom the auxiliary passage [3 sweeps the nozzle portion longitudinallyfrom base to tip, and protects it from access of the molten metal andslag that trickle and rain from the furnace charge above.

The angle of the passage [3 with respect to the vertical axis of thefurnace is so determined that the stream of air jetted upwardly by thepassage is directed into the charge above the tuyere-line of thefurnace, with the good effect already described, that better penetrationof the air blast into the furnace charge is obtained, and the depth ofthe zone of metallurgical reaction in the furnace substantiallyincreased.

In further elaboration of usual tuyere construction, a second auxiliarypassageway, l4, may be provided in the tuyere. This passageway extendsdownwardly from the tapered throat of the tuyere and opens, as thepassageway l3 opens, in the end wall 21) of the tuyre body. Thus, thenozzle portion of the tuyre is swept both above and below by protectingstreams of air.

The air streaming downwardly from the passage l4 plays upon the surfaceof the bath of molten metal on the furnace hearth, accelerating thecombustion of the unburned coke that normally floats on the bath, and inconsequence maintaining the molten metal at higher temperature and inmore uniformly fluid condition.

The tapered form of the bore 1 of the tuyere is important. The bore, soformed, provides with the cylindrical passageway of the nozzle portionI2 a Venturi-shaped throat, whereby the air delivered by the blow-pipe 9flows from the tuyere passageways with accelerated velocity.

The wall of the nozzle portion l2 of the tuyere will ordinarily behollow, as shown in Figs. II and IV, to the end that such nozzleportion, as Well as the main body of the tuyere, may be Water cooled.And the engineer will perceive that the tuyre structure may be formedeither of assembled sections, or of an integral casting, as hereinillustrated, with openings I5 for the passage of cooling water betweenthe chamber Ill and the recess within the hollow walls of the nozzleportion. However, it is to be noted that the protection, which theauxiliary streams of air afford the nozzle portion, is so effective inmy structure that the wall of the nozzle portion may be, and in manycases will be, of solid construction.

Referring particularly to Fig. I, it will be seen that the tuyere holder5 is built into the furnace wall 6 with its inner end flush with theinner surface of the furnace wall; that the tuyere, seated in theholder, projects from the furnace wall inward; and that the emergence ofair into the furnace charge, both through bore 1a of the nozzle portionand through the auxiliary passageways l3 and I4, is into a portion ofthe charge that is spaced inwardly and remote from the furnace Wall.Thus, while the depth of the zone of metallurgical reaction isincreased, the region of intense reaction is carried inwardly from thefurnace wall toward the centre of the charge, leaving the furnace wallprotected by intervening material from such intensity of reaction aswould effect its rapid destruction. Furthermore, the nozzle portion I2is swept externally by the streams of air that emerge from passagewaysl3 and I4, and is thus hielded from the high temperature of the reactionzone.

Fig. V serves to illustrate that the extending nozzle portion of thetuyre may be varied in cross-sectional form. Here the nozzle portionI20, is shown to be elliptical, with the outlets of the auxiliary airpassages l3a and Ma appropriately modified in shape and in position.

To the extent that the protection of the centrally extendng nozzleportion of the tuyre is of prime importance, the number of the auxiliarypassages (I3, l4) may in some .cases be increased, with the efiect thatsubstantially the entire exposed surface of such nozzle portion will beenveloped by a protecting curtain or sleeve of air. And if it should befound in particular installations that the effect of the auxiliarystreams of air upon the metallurgical reactions within the furnace isonly of subsidiary importance, the directions of flow of the auxiliaryair streams may be modified, with the protection of the extending nozzleportion of the tuyre the primary consideration.

I claim as my invention:

1. In the operation of a metallurgical furnace that involves chemicalreaction under aeration at the base of a gravitationally descendingcharge by means of an air nozzle that projects inwardly from the furnacewall, the method herein described of protecting the nozzle and extendingthe depth of the zone of reaction which consists in releasing within thecharge and at a point remote from the furnace wall an inwardly directedstream of air, and, at a point to rearward of the point of release ofsuch stream, but also a point inwardly remote from the furnace wall,releasing an inwardly and upwardly directed supplementary stream of air.

2. In a metallurgical furnace that includes a hearth, a bosh arranged atan interval above the hearth and adapted to sustain a furnace charge,and a tuyre arranged beneath the bosh and adapted to deliver through itsmain orifice and to a charge within the furnace and above the pool ofmolten metal collecting on the hearth a reaction-sustaining stream ofair, the invention herein described which consists in an elaboration oftuyere structure in the form of a supplementary orifice opening on theupper side of the assembled tuyre and torearward of the main orifice andadapted to deliver an upwardly and inwardly directed supplementarystream of air, whereby such supplementary stream sweeping and protectingthe upper surface of the forward portion of the tuyere penetrates thecharge and increases the depth of the zone of metallurgical reaction.

3. In a metallurgical furnace that includes a hearth, a bosh arranged atan interval above the hearth and adapted to sustain a furnace charge,and a tuyere arranged beneath the bosh and adapted to deliver throughits main orifice and to a charge within the furnace and above the poolof molten metal collecting on the hearth a reaction-sustaining stream ofair, the invention herein described which consists in an elaboration oftuyere structure in the form of supplementary orifices opening one onthe upper the other on the lower side of the assembled tuyere and torearward of the main orifice and adapted to deliver upwardly andinwardly directed and downwardly and inwardly directed supplementarystreams of air, whereby such supplementary streams sweeping andprotecting the upper and lower surfaces of the forward portion of thetuyre penetrate the charge and increase the depth of the zone ofmetallurgical reaction.

4. A tuyre for a metal-reducing furnace having a forwardly taperingbore, a cylindrical nozzle portion constituting a main air-deliveringpassage extending on the axis of the bore and forwardly therefrom and anauxiliary passageway extending from the forwardly tapering bore anddelivering externally of and at the rearward end of said cylindricalnozzle portion.

5. A tuyre for a metallurgical furnace that consists of a body offrusto-conical form with an interior passageway correspondingly tapered,and adapted to be mounted in inwardly projecting position in a furnacewall and with the smaller base of the frustum disposed in Vertical planeand spaced inward from the furnace Wall, the tuyre having a cylindricalnozzle portion forming an axial continuation of the said taperedpassageway and an auxiliary passageway extending from such interiortapered passageway obliquely forward and opening through the smallerbase of the frustum exterlorly of and at the base of said nozzleportion.

FRANCIS J. ZIPPLER.

